Tabmanager.io

Pros: Allows for organizing tabs into groups.
Has limited drop & drag functions.
Reinstates tabs without reloading websites.
Provides features like searching URLs and page titles.
Good for managing tab groups across windows.
Works without problems.

Cons: UI needs improvement.
Lacks modern design.
Lacks certain functions like tab favicons, drag & drop integration, and merging capabilities needs some more options
Tab groups will not "expand" in save sessions or history.
No user guide or customer support.
Auto-save session feature is wonky

Overall: This app offers some of the better user features so far compared to some other apps I have used. (except Skeema, which is retiring June 28th, it's in a league of its own). Session Buddy is close but has no "drag & drop" or Chrome "groups" integration feature yet, but has a better UI. There are quite a few functions that need to be added or fixed, however. For one thing, the UI needs to be more modern, like Session Buddy UI. Tab "Favicons" does not show in the list of tabs, most all other apps have that feature. There is no way to click on a tab and then click on the "control" or "shift" key to select multiple tabs to move, drag, or drop the selected tabs into another window/session/collection. "Drag & drop" will not work in saved session windows or history. Clicking the "arrow" to "expand" saved tab groups does not work, (except in the address bar), it will not show what tabs are in the group in saved sessions or history windows. When the mouse hovers over a saved session, it should show the number of tabs, the date created, and the last update. The merging function needs more work, it adds duplicates of merged tabs. Active session and history windows are not offered to merge with saved session windows in the menu popup box. Naming windows in open sessions with random numbers is very confusing, there has to be a better way. The size of the left side window should be adjustable and a way to "lock" it open. There should be a way to open & show all of the content of open session windows along with all the content of saved session windows in the large middle "list view" screen so new current session tabs and groups can be dragged and dropped into previous saved session windows collections. Is there a way to select a color for sessions or saved collection folders? Also, I do not see any "settings" menu to adjust the History settings (auto-save intervals etc.). I cannot locate any "user guide or "help" for the app. Customer support does not seem to exist. I have tried to contact customer support numerous times and do not receive any response from them.